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BULLETIN OF THE 




No, 9 




Contribution from the Forest Service, Henry S. Graves, Forester 
December 5. 1913. 



AN ECONOMIC STUDY OF ACACIAS. 

By Charles Howard Shinn, 
Forest Examiner. 

PURPOSE OF THE STUDY. 

The acacias are so valuable as a source of tanning material and of 
timber, and are so well adapted to the reclamation of sandy and semi- 
desert lands that the introduction and culture of these exotics into 
certain portions of the United States may prove extremely profitable. 

To a certain extent parallels exist between the culture, in America, 
of eucalypts and aca'cias. Both were introduced in California about 
the same time, and both have thrived there. Commercially, too, 
their ranges are practically identical, though acacias do not make as 
large demand upon the soil. In both cases, however, the lack of 
frost hardiness limits their range. 

The aim of this bulletin is to call attention to the economic impor- 
tance of the leading acacias with the idea of bringing about more 
general planting. 

THE GENUS ACACIA. 

ITS EXTENT. 

The acacias form the most characteristic group in the suborder 
Munosese, .of the great bean family Leguminos^, represented in the 
United States by such trees as black locust (Rohinia pseudacacia) , 
honey locust (Gleditsia triacanthos) , coffee tree (Gymnocladus dioicus) , 
and redbud (Cercis canadensis). They are, in the main, natives of 
Australia, which has about 300 species. There are 150 other species 
scattered over the world, principally in Asia, Africa, and America, 
with one important species, the koa, in the Hawaiian Islands. Of the 
450 not more than 75 have a known economic value, and not more 
than 50 are in general cultivation, though 150 species are growing in 
nurseries, gardens, and arboretums in the United States. A com- 
pilation of California nursery catalogues made in 1911 showed 103 
species listed. The authorities of Golden Gate Park, San Francisco, 
enumerate 60 species growing withm the park. 
6746°— 13 1 



:vU ? 



2 BULLETIN 9, U, S. DEPARTMENT OF AGEICULTUEE. 

Besides the 450 species there are many varieties developed through 
cultivation. Further, much confusion exists as to the proper identi- 
fication, not only of the acacias but of closely related genera, which 
are sometimes confused with the true acacias. An example of this 
is found in the so-called Acacia lophantha, which is an albizzia, as is 
the pink-flowered "Constantinople acacia." The flowers of the true 
acacias are usually yellow, and are produced in globose heads vari- 
ously arranged ; those of' the albizzias are generally borne as spikes, 
similar to those of the Australian " bottle brush " (Melaleucas), and 
are seldom yellow, though some are a greenish white. 

NOMENCLATURE. 

The difficulties of identification have led to equal difficulties of 
nomenclature, or, rather, the confusion in either case has led to 
confusion in the other. Except for the species of greatest economic 
value, which have been longest in cultivation, the nomenclature is 
so mixed in California that acacias are still being sent to Dr. Maiden, 
director of the Sydney Botanic Garden, for identification. 

Mr. Ernest Braunton, of Los Angeles, has done much in recent 
years to secure the correct identification of the acacias planted for 
ornament in southern California. Dr. Franceschi and Mr. P. Reidel, of 
Santa Barbara, and Miss Katherine Jones, of the University of Cali- 
fornia, at Berkeley, have worked with the acacias to the end that the 
synonjmis may be all weeded out, and that the various species grown 
in California, where acacias have been most extensively planted in 
this country, may be accurately known. 

The chief difficulty has been with the so-called decurrens group, 
and the problem has been to distinguish between species and mere 
varieties. 

The classification made by Dr. J. H. Maiden ^ seems to be both 
culturally and scientifically correct, and its general adoption offers 
the best escape from present confusion in American nomenclature. 
Accordmg to this (1) Acacia decurrens, or decurrens var. normalis 
(Willd. and Benth.), is the "black wattle"; (2) Acacia decurrens var. 
mollis (Benth.) is the Acacia mollissima (Willd.), and is the leading 
"green wattle"; (3) Acacia decurrens var. pauciglandulosa (F. von 
M.) also is known usually as "green wattle"; (4) Acacia decurrens 
var. dealbata (F. von M.) is the leadmg " silver wattle." 

These fom- wattles and two or tliree others of lesser importance 
pass into each other by successive gradations. They show cultural, 
differences, however, and marked variations in yield of tan bark. 
The nurseryman naturally chooses the more floriferous and shapely 
form of Acacia decurrens, but the commercial planter must consider 
bark yields and proportion of tannin. 

1 " Wattles and Wattle Barks," third edition, pp. 103, Sydney, 1906. 



Ac) <o ^^ ECONOMIC STUDY OF ACACIAS. 3 

(yy ^ CHARACTERISTICS OF VARIOUS SPECIES. 

SOIL AND MOISTURE REQUIREMENTS. 

Acacias form one of the most conspicuous associations of all those 
which group themselves close to deserts. While they do not con- 
stitute a true desert species, they nevertheless carry tree life well 
into the desert regions, becoming shrubby and scattered. In fact, 
some species, such as Acacia greggi, one of the most valuable lac-insect 
bearing species, will tlnive with only 3 inches of rainfall; some 
gi'ow on inland sand dunes far from ocean influences. With a few 
notable exceptions, the acacias are preemmently adapted to poor 
soil and ramless summers and to semiarid conditions, though most 
of them respond to good soil and abmidant moisture. Their great 
drought-resistmg qualities come from their deep, strong root systems 
and from their leaves, which are chiefly phyllodes, or flattened 
stems, with sensitive specialized powers of movement by which 
evaporation may be greatly lessened. 

A light, warm, well-drained soil, if cultivated, will produce rapid 
growth, and the rich and heavy soils which some of the eucalypts 
demand for their best development are not necessary for the acacias. 
The most promment exception to this is Acacia melanoxylon, or "black 
wood," which produces choice timber but has little value for tamiing 
unless the tannic acid is concentrated by the extract method. This 
is a river-bottom species, associated with Eucalyptus globulus and 
other trees of that type. 

Acacias readily adapt themselves to a heavier precipitation and 
more tropic conditions than characterize their native soil, as proved 
by many years of growth in the Hawaiian Islands and on the Natal 
coast of Africa. Indeed, many species, as with the eucalypts, when 
mtroduced elsewhere, may grow even more rapidly than in their 
native region. But mainly the significant fact about the tree, so 
far as moisture conditions are concerned, is that it does not require 
a heavy annual rainfall nor any summer ram. It is this character- 
istic which renders it valuable on the southern Pacific coast and in 
the Southwest. It must be kept in mind that the trees are only 
half hardy as regards frost, and will not endure a temperature below 
16° F. or 20° where the cold is likely to be sustained. 

So far as 'known, no other semitropic trees of high economic value 
possess to so great an extent the ability to thrive upon and to 
improve a great variety of arid and sterile soils. Through their 
agency large areas of land mifit for ordmary cultivation, and at 
present producing only a scanty pasturage at best, may be reclaimed 
and utilized. Recent discoveries in the nitrogen-fixmg qualities of 
the legumes pomt to the possibility of a hitherto unrecognized value 
in acacia growing. 



4 BULLETIN 9, U. S. DEPARTMENT OF AGRICULTURE, 

FORMS. 

With so many and st) varied species there can ])e no form and no 
rate of growth common to the whole genus. Some acacias are mere 
herbaceous plants; others are towering trees; most are shrubs, and 
some, in fact, are vines or chmbers. In certain instances the same 
plant which has a creeping habit when exposed to cold salt winds 
on the seashore will be able, a little farther inland, to assume an erect 
form and, where still better protected, to become a fully developed 
tall tree. One authority describes these size variations thus : 

Some tiny species hardly exceed 3 or 4 inches in height, and may be crushed like 
the grass of the field. Most of them are shrubs, or trees of moderate size, while at 
least two species attain the stature of large forest trees, both of them being found to 
measure up to nearly 4 feet in diameter, while one has been found to attain a height 
of over 100 feet, and the other the extraordinary height of 150 feet.' 

The largest acacia is probably Acacia halceri, of which specimens 
have been described as over 160 feet high, wdth a clesCr length of from 
50 to 60 feet and diameters of from 2 to 4 feet. Other large trees are 
Acacia melanoxylon, A. longifolia, A. dealhata, and A. decurrens, all of 
which may attain a height of 100 feet or more. A. salicina, A. excelsa, 
A. data, A. iirominens, A. ijendula, and A. iinervata are also large 
trees, ranging from 30 to 80 feet in height. 

Those which are most used for commercial products, and par- 
ticularly for tannin, do not need to attain large size or great age 
before the products are merchantable. Thus they can be managed 
on a shorter rotation than most forest trees. 

ENEMIES. 

Insects. 

The acacias first planted in California grew so fast, bloomed so 
soon and so freely, and were so free from disease that most horti- 
culturists felt sure that acacias would become the most important 
shade trees for California. This enihusiasm w^as particularly marked 
from 1870 to 1876. It was like tlie subsequent fad in the Middle 
West for the hardy catalpa or the more recent furore over eucalypts 
in California. There followed, however, a sharp reaction because 
of the ravages of various scale insects, and many trees were cut down. 
But after the introduction of the vedaha, wliich destroyed the cottony 
cushion scale, and the adoption of the various sprays it was found 
that the acacias are not pecuUarly subject to injury by scale insects, 
and are no more often a haven for the pests than are oaks, ohves, 
and various orchard trees. The most dangerous insect enemy, 

» J. H. Maiden, "Wattles and Wattle Barks," Government Printer, Sydney, New South Wales. 

2 For information on insects and methods for their control the reader should apply to the State Experi- 
ment Station, Berkeley, Cal., or to the Bureau of Entomology, United States Department of Agriculture, 
Washington, D. C, 



AN ECONOMIC STUDY OP ACACIAS. 5 

according to various observations, is the cottony cushion scale 
{leery a pumcliasi). 

The scale insects have sucldng mouthparts and subsist on the 
juices from the inside of the tree; for this reason they are hard to 
combat, because it is difficult to poison their food supply. Since 
they live upon the sap, they must necessarily lessen the vitahty of a 
tree, especially where there is a very dry summer cUmate. If they 
are very numerous, trees can not thrive and may even be killed. 
Scale insects, besides robbing the tree of nourishment, harm the 
tissues, close the pores by their excretions, and supply conditions 
under which fungi may get a good start. All these are much less 
serious with the acacias than the actual loss of sap; and where 
the water supply is ample the actual harm done by the scale is very 
shght. But since one of the chief values of the acacias is their 
adaptabihty to very arid regions, the scale insects should be destroyed 
wherever they exist, and care should be taken to estabUsh plantations 
from seed or from thorouglily disinfected plants. 

Two insect enemies of the wattle in Natal, reported by Mr. David 
G. Fairchild, are a bag worm, which destroys great quantities of 
foliage and checks the growth of the trees, and a more destructive 
locust, which can retard growth to the equivalent of more than a 
year. The bag worms are collected and burned, and the plague of 
locusts is prevented by spreading poisoned molasses about their 
breeding places. A special locust expert is employed by the Natal 
Government; with his corps of laborers he poisons all the principal 
breeding places of the pest. 

Other insects attack the black wattle {Acacia decurrens) in Austra- 
lia.^ Of these, one is an undescribed species of weevil {Bruclius sp.) 
wliich was found in seeds purchased in San Francisco, and pre- 
sumably was introduced into California from Australia or South 
Africa in the seed. Another is a long-horned beetle {CyeJle crini- 
cornis) of almost world-wide distribution in the Tropics; several 
other insects do more or less harm. 

Fire. 

There seem to be various opinions about the fire-resistant qualities 
of acacias, though they are generally considered very sensitive to 
fire. Some authors have stated that they do not burn readily, 
and the wattles in particular have been recommended for planting 
as fire breaks, not so much because they are not easily ignited but 
because their growth is so dense, both above and below ground, that 
no ground cover can thrive, and there is, therefore, beneath the trees 
an area free of vegetation. On the other hand, Dr. Maiden says - 

1 "The Black Wattle," by Jared G. Smith, Bulletin No. 11, Hawaii Agricultural Experiment Station. 

2 "Wattles and Wattle Barks," Sydney, 1906. 



6 BULLETIN 9, U. S. DEPAETMENT OF AGRICLTLTUKE, 

that wattle plantations must be protected from fire by fire breaks 
''and also by the removal of the mflammable brush from among 
them. At the same tune, the finely divided foliage of Acacia decur- 
rens makes it the most susceptible of the conmaercial wattles to 
destruction by fire. " In Natal, accordmg to Mr. David G. Fair- 
child— ^ 

The greatest enemy of the wattle is the grass fire. From the sm-rouhding prairie 
such fires spread into the plantations and destroy them. To prevent this, nearly 50 
miles of fire breaks, made by planting broad strips of prairie, have been constructed 
about the forests, and the expense of this adds materially to the original cost of estab- 
lishing a wattle estate. 

Another author, writing from the Transvaal,^ calls attention to the 
prevailing notion that "it is commonly supposed that wattles a few 
years old are safe from fire, and in fact make good fire breaks. This, 
however, is not the case, and many disastrous fires have entirely 
destroyed wattle plantations. " A fire which merely defoliated the 
trees scorched the bark and rendered it valueless. "From this it 
will be seen how very necessary it is to protect the' plantations from 
fire as far as possible. This can best be done by plowing or burning 
wide belts around the trees, " and by dividing the plantation into 
blocks by means of roads, which must be kept clean. 

Other Injuries. 

Frost is, of course, to be avoided, though many species will stand 
temperatures of 20° F. if not too prolonged. Hail may do consider- 
able damage by bruismg the bark and breaking off shoots. Crooked 
stems and branches have resulted from hail mjury. 

A black-wattle plantation in Hawaii suffered a loss of 20 per cent 
due to three causes — ^from being overmature, from stock browsing, 
and from insect enemies. Goats are particularly injurious, and their 
severe cropping will altogetiier destroy growth. 

HISTORY OF ACACIA CULTURE IN CALIFORNIA. 

Those who first planted acacias m California obtained only the 
species which had been planted on the Atlantic coast and in the Mid- 
dle West. Many of these species were not in the least adapted to the 
California climate. It was then suggested that since western Mexico, 
Chile, and southern Europe had climates similar to that of California, 
acacias from these regions would be suitable, but introduction was 
slow and difficult. The Spanish settlements had furnished a few 

1 Bulletin 51, Bureau of Plant Industry, Miscellaneous Papers, "The Cultivation of the Australian 
Wattle," pp. 21-25. 

2 Lionel E. Taylor, Assistant Conservator of Forests, in Forestry Section of Transvaal Agricultural 
Jcumal, Jan., 1910, vol. 8, No. 30, Agricultural Department, Pretoria. 



AN ECONOMIC STUDY OF ACACIAS. 7 

species which were extensively propagated, and one of them, Acacia 
farnesiana, faniiliar about the missions of San Diego and Santa Bar- 
bara, was grown by nurserymen m San Francisco, Los Angeles, and 
Sacramento as early as 1854. Potted acacias and acacia flowers, 
grown at Sacramento, were exhibited at one of the first agricultural 
fail's held in California, in 1855. An Australian acacia bloomed at 
Marysville before 1860. 

The importation of acacia seed from Australia began in a curious 
way. A few of the Australians who came to California at the tune of 
the gold fever brought over seeds and rooted plants and sold them 
to the nurserymen at high prices. By 1853 Col. Warren, who had 
established the California Farmer, was obtaining Australian seeds 
from these immigrants, and was soon importing direct from Sydney. 
In 1854 he was advertising acacia seed, and nurserjanen in the vicinity 
of San Francisco were plantmg Acacia decurrens and Acacia mela- 
noxylon. These two species were the pioneers of the Australian 
acacias m California. Acacias from these early importations were 
bloommg and attracting attention in San Francisco, San Jose, and 
Sacramento by 1858. 

By 1862 the late Julius Forrer, a German, for a long time the capa- 
ble foreman of one of the University of California experiment stations, 
was growing in his nursery m San Francisco these species: Acacia 
cyanopJiylla, A. cuneata, A. dealbata, A. JiomalopJiylla , A. linearis, A. 
.longifolia A. lunata, A. melanoxylon, A. " mollissima" (A. decurrens 
var. mollissima) , A. pendula, and A. receana. 

Between 1870 and 1875 enthusiam in p,cacia planting was at a high 
pitch. This was followed by a sudden reaction due to the introduc- 
tion and depredations of scale insects. Since 1880, ho\fever, Cali- 
fornia nurserymen have increased then- stock of acacias, and smce 
1900 sales have been much greater, especially in southern California, 
where some growers make a specialty of it. Mr. Wolleb, another 
German, of Fruitvale, Alameda County, bought trees from Forrer's 
nursery from 1862 to 1870 and tested many other species. In 1882 
he published in the Rural Press a review of his experiments. He 
had tested Acacia armata, argyrqfolia, hinervata, celestrifolia, cultri- 
formis, cyanopJiylla, dentifera, discolor, farnesiana, extensa, pulchella, 
latifdlia, saligna, linearis, longifolia,, lunata, nigricans, nerifolia, 
receana, suavolens, verticillata, vestata, and some others now dro'pped 
from cultivation. 

Other Californians besides Mr. Wolleb made collections of acacias 
before 1880 and kept notes on their growth. The late Gen. John Bid- 
well planted some m Chico, Butte County, in the Sacramento Valley, 
and they are now magnificent specimens. A few were set out in 
Shasta City, about 200 miles north of San Francisco, and still flourish. 



8 BULLETIN 9, V. S. DEPAETMENT OF AGRICULTURE. 

Mr. Alviiiza Hayward, Mr. P. Nolan, and Mr. H. P. Livermore 
planted tliem extensively in Alameda County; J. de Barth Shorb 
niade a 10-acre plantation in Los Angeles County about 1875. This 
plot has since been cut up into city lots, but some of the original trees 
remain. 

The College of Agriculture of the University of California and the 
State Forestry Commission grew and distributed many acacias, and 
have published the results of successful investigations. The collec- 
tion of acacias at Berkeley, the seat of the State university, was begun 
in 1872 with 30 species, and was subsequently augmented by many 
others. Parts of the arboretum were destroyed, however, to make 
way for new buildings. Acacias were planted at Chico and Santa 
Monica forestry stations, and at the latter place tannin determina- 
tions of the bark have been made. Acacia planting in Golden Gate 
Park, San Francisco, was begun by Mr. W. H. Hall, the superintendent, 
in November, 1870, when 1,200 acacias of 10 species were set out. 
Planting went on year after year under the supervision of the man- 
ager, Mr. John McLaren. In 1880 and 1889, 50,000 acacias were 
planted in the sands toward the western end of the park. In the 
years 1889 to 1892 not less than 50,000 trees, and usually 60,000 trees, 
were set out in a season, and in subsequent years from 5,000 to 20,000 
were used each year, so that up to the present time about half a 
million have been planted. The Golden Gate Park nurseries still 
grow about 25,000 specunens every year, and they haA^e more acacias 
and more kinds of acacias than anywhere else on the Pacific coast. 
This Golden Gate Park planting is such a remarkable example of 
sand-dune reclamation that it will be treated alone in a chapter 
devoted to. that subject. 

This review of acacia planting in California since 1852 shows that 
the field has been very fairly covered. Any person who desires to 
know whether a given species of acacia will thrive in any part of 
California is likely to find mature specimens within a reasonable 
distance. He may not find commercial or profit-yieldmg plantations, 
but he will find ample evidence of the adaptability of the tree to the 
soil and climate. Just as the olive and orange trees of the missions 
proved the suitability of the region to olive and orange groves, the 
many acacia trees, over a much wider range of country, show the 
commercial possibility of acacia plantations. The hardier acacias 
will flourish where the orange and olive will succeed. Nevertheless, 
many species have not yet been fully tested, and there is need of 
further systematic determination of the frost and drought limits, 
even of long-cultivated species; also for exact tests of bark yields 
and proportion of tannin. The naturalization of any exotic on a 
large scale requires much patience and money and involves complex 
problems. 



Bui. 9, U. S. Dept. of Agriculture. 



Plate I. 




^^:«^:^j:^2^fsmi^iv:'f-^f('fj^^''' ■■' .. iM^ 



A Plantation of Acacia decurrens mollis in Golden Gate Park, San Francisco. 



Bui. 9, U. S. Dept. of Agriculture. 



Plate II. 




Acacia arabica, One of the Sources of Gum Arabic, at the Santa Monica Forest 

Station, California. 



3ul. 9, U. S. Dept. of Agriculture. 



Plate III. 




Fig. 1.— Thickets of Albizzia lophantha Near the Ocean, Golden Gate Park, 

San Francisco. 




Fig. 2.— Thickets OF Acacia longifolia Almost at the Edge of the Tide, Golden 

Gate Park. 

The plant with the finer foliage is the acacia. 



AN ECONOMIC STUDY OF ACACIAS. 9 

ECONOMIC USES. 

The acacias were first spread abroad over the semitropic regions of 
the earth by reason of their easy culture, their adaptibihty to many 
situations, and their attractiveness as shrubs or shade trees. Their 
wide range of economic uses, however, was very slowly recognized 
outside of Australia, where many species have long ranked with the 
eucalypts as profit-yielding trees. Some acacias have a remarkable 
value for the reclamation of sand dunes, whether they are seashore 
drifts or inland barrens. Many species furnish tanbark; others yield 
forage; others produce timber of notable quality; almost all are 
suited to ornamental plantings, and many are excellent for sti'eet 
trees and for shelter belts, and several furnish many special products 
of great economic value. In fact, various ^ecies of Australian 
acacias, according to Dr. Maiden, yield food, forage, medicine, fibers, 
gums, resins, kinos, perfumes, dyes, tannins (33 Australian species 
furnish tannin in commercial quantities), timbers, and ornamental 
finishing woods (at least 50 Australian species furnish valuable wood) . 
Many Indian and African species furnish timber, gums, tanbark, 
catechu, and other products, and furnish host plants for the valuable 
lac insect (Tacharia lacca). The American Acacia greggi also fur- 
nishes lac. A. farnesiana, which is found in both the New and the 
Old World, is the famous ''popinac" or "cassie" perfume plant so 
largely grown around Grasse in France. 

Thus the farmer, the lumberman, the furniture maker, the stock 
raiser, the tanner, the perfumer, the chemist, and many others are 
interested in acacias, and the more useful species are properly recog- 
nized as being worthy of establishment over large areas, and of man- 
agement on principles of forestry. The recognition of this fact has 
been notable during the last 10 years, because the best species of 
acacias are rapidly disappearmg from their native countries, except 
where they have been mtelligently protected and planted; and, 
further, because so many countries have successfully introduced 
acacia culture. 

ACACIAS FOR SAND-DUNE RECLAMATION. 

The acacias have great value as a ground cover, for dunes near the 
ocean, and for mland sand barrens, almost to desert conditions, smce 
they will thrive with only a few inches of rainfall, provided it comes 
at such a time that the seeds can become rooted, and provided the 
temperature does not fall below 20° F, "Where the average rainfall 
is not less than 20 mches and the summers are cool and the winters 
mild, almost any trees can grow if they get a start; what is needed in 
the first place, therefore, is some growth which will hold the driftmg 
sands, binding them until a more stable soil, with some humus, is 
formed, and paving the way for valuable trees. This need is supplied 
by acacias. 

6746°— 13 2 



10 BULLETIN 9, U, S. DEPARTMENT OF AGRICULTUEE. 

Almost all west coasts present similar problems, not essentially 
different from those which have been successfully solved by Bremon- 
tier m France, and by Reventlot in Denmark. 

The California dunes, the French landes, the Dutch 'polders, the 
Danish heaths, and the barrens of the Baltic coast of Prussia are all 
in the same category. Abroad the abundant use of the sea reed 
AmmopJiila arenaria is of first importance; but in the warmer regions 
of the globe the acacias can always follow the grasses. In some 
instances, if the acacias are freely used, they may entirely o])viate the 
need for the preliminary grasses. In these warmer climates the low- 
growmg acacias arc much preferable to the broom and gorse so useful 
hi more northern latitudes, while the larger acacias grow much faster 
than most other trees. 

Abroad. 

AFRICA. 

The experience of several countries with acacia plantations near 
the shore emphasizes their desirability on such soils. 

Cape of Good Hope. — The official reports of the conservator of 
forests. Cape of Good Hope Colony, vSouth Africa, gives the results of 
extensive reclamation of sandy regions near the shore. For nearly 
30 years these "blue books" have been crowded with mformation of 
mterest to those who have to deal with the problem of fixuig sands. 

While acacias were first grown in South Africa for tanbark, fire- 
wood, and other uses, their value in makmg productive the enormous 
sand wastes was soon recognized. Such situations were extensively 
seeded, sometimes with acacias alone, and sometimes in com])ination 
with cluster pine (Pinus pinaster), the favorite conifer of the South 
African planter. The prmcipal species were Acacia leiopJiylla Benth., 
(Acacia saligna, Wendl.), Acacia longifolia Willd., and Acacia 
pycnantha Benth., all of which yield tanbark, besides some of the 
larger wattles, such as decurrens, together with many of the lessor 
shrubby species. The climiitic conditions are often more detri- 
mental than those which prevail on the California sea coast, and the 
labor problem is certamly no more satisfactory. 

Now that the plantations are well established, the seed from them 
and from other older plantations is gathered cveiy year at small cost. 
In 1891 about 1,600 pounds of acacia seed were sown, or distributed 
to the public; the next year, 4,000 pounds, 1,963 of which were 
A. leiopJiylla. By 1898 the forest officers reported an annual sowmg 
of 4,840 pounds of A. leiophylla seed and 4,360 of the shrubby A. 
Cyclops. Summmg up, not less than 20,000 pounds of acacia seed of 
various species were sown or distributed to planters m South Africa 
between 1888 and 1899. 

Port EKzaheth.— In 1892, at Port Elizabeth, South Africa, 150 
acres of drifting sands were reclaimed bv the broadcast sowing of 



AlSr ECONOMIC STUDY OF ACACIAS. 11 

A. leiopliylla, cy clops, and pycnantha. Since the sand was very loose 
and fine, stakes interwoven with brush were first used to keep the sand 
from shifting, while the seeds were getting a start. The experiment 
was an entne success. The ramfall that year was about 16 inches. 
By 1896 more than 2,000 acres had been reclaimed at Port Elizabeth. 
In the choice of species it was planned that the smaller growth, such 
as A. Cyclops, would bind the soil and enable the larger tanbark acacias 
to become established. During the South African war little was done 
to extend these plantations, but since then operations have steadily 
progressed. 

The Port Elizabeth experiments demonstrated that broadcast 
so whig was not only feasible, but in this case seemed advisable. It 
costs from 4 to 6 cents a pound to gather acacia seeds from the bearmg 
plantations. When the plantations were young the seed was drilled 
in at the rate of about 12 pounds to the acre. At this tune, however, 
a much thmner sowuig is usually considered better, and from 1 to 2 
pounds only are sown to the acre, which would make the seed cost 
not more than 12 cents. 

Port Jaclcson. — Acacias are bemg sown on drifting sands in South 
Africa in many other places besides Port Elizabeth, but the details of 
the plantmg are likely to vary with local conditions. At Port Jack- 
son seed was sometimes sown m alternate rows with cluster pmes, 
in some cases compartments or blocks of the plantation were entirely 
the one or the other. Agaui, rye or barley was sown thmly with 
the acacia or pine seed to give a quick buider and some shade. Ten 
years after plantmg the official report on these experiments states: 
"The sands have undoubtedly been fixed, and generally the trees 
have been domg well." The cost of these sowings ranged between 
S2.75 and $6 an acre. Wages were low, and it was practically all 
handwork, with but little use of labor-saving methods. The greatest 
expense was the fillmg m of gaps with nursery-grown plants, but 
this was seldom necessary. 

ELSEWHERE. 

Much additional evidence might be compiled from sand-bindmg 
m Natal, New Zealand, AustraUa, and the Mediterranean shores, 
but that which has been cited is sufficient to offer important sugges- 
tions for American practice. It has been conclusively proved that 
16 inches of ramfafi is ample; that it is an unnecessary expense to 
use nursery-grown plants; and that by usmg a mixture of shrubby 
and arborescent species, the larger tanbark and timber yielding trees 
can be started from the begmnmg of the operations. Acacia cy clops 
is valuable only for sand reclamation; the shrubby type of A. longi- 
folia is quite as satisfactory. Even A. longifolia might be superseded 
h J A. leiopliylla, which resembles A.cyanophyUa; it readily sends up 
shoots when cut down, and its bark contains from 30 to 35 per cent of 
taniim, which makes it a valuable commercial species. It is useful 



12 BULLETIN" 9, U. S. DEPAKTMENT OF AGEICULTURE. 

also for firewood, as well as for fences and windbreaks. The Acacia 
pycnantJia used in South Africa is the superb "golden" or broad- 
leaved wattle of South Australia, which yields one of the richest tan- 
barks m the world. 

In California. 

California has large areas of sand along the coast, more or less cov- 
ered with beach plants, such as the abronias, lupins, and artemisias. 
Such sand areas have but little value, and have not improved in the 
past 50 years. These and similar areas in the Mojave region and the 
upper Salinas Valley can be readily reclaimed by the use of acacias, 
which can be selected not only for their sand-binding qualities but for 
their value as pasturage and as supplies of fuel wood and tannin. On 
such sand wastes the covering of shrubby acacias can be secured by 
sowing seed with the first rains in the fall. If the forage-yielding 
Australian "myalls" and "mulgas," such as Acacia pendula, salicina, 
and aneura, are chosen, they are likely to prove the most profitable 
crop that can be grown on such soils. Alhizzia lophantha belongs 
with these as a shrub for browse. All of these species readily repro- 
duce themselves, widening their extent along the seacoast, and will 
eventually produce a large amount of firewood. 

As a matter of fact, acacias which have escaped from cultivation 
have become naturalized in many places along the California coast. 
There are thickets near the ocean between Watsonville and Santa 
Cruz, also near Morro, San Luis Obispo County, along the coast in 
Sonoma County, and likewise a few miles from Santa Monica. In a 
gulch near Carpinteria, south of Santa Barbara, there are self-sown 
seedlings and also large trees of Acacia decurrens, melanoxylon, and 
longifolia, which have grown from the stumps -of older trees. Near 
old Ventura Mission there is the same adaptation of the Australian 
acacias to the California coast and foothills, even where they receive 
no care whatever. 

In many cases the smaller acacias merely serve to fix the sand, and 
will properly give way to the larger acacias, to eucalypts, pines, 
casuarinas, and other timber trees. One large district which can be 
reclaimed in this way covers many square miles of coast in Monterey, 
San Luis Obispo, Santa Barbara, and other more southern counties. 
The same is true of large areas north of Monterey and about San 
Francisco, and of large inland areas where the sand is decomposed 
granite, adapted to Acacia aneura and A. salicina. Von Mueller 
recommends Acacia excelsa and the very shrubby form of Acacia longi- 
folia, as valuable sand binders; both yield tanbark. According to 
the same authority, Acacid: giraffea (Willd.), of South Africa, and 
Acacia seyal, of the Nubian Desert (neither of which has been tested 
in California) , are especially drought resistant and have great economic 
value. 



AN ECONOMIC STUDY OF ACACIAS. 13 

GOLDEN GATE PARK, SAN FRANCISCO. 

The best evidence of the adaptation of nearly all of the Australian 
acacias to the sandy soil of the California seacoast, clear down to the 
ocean beach, directly exposed to heavy gales and dense salt fogs, is in 
Golden Gate Park, San Francisco, where they have been chiefly in- 
strumental in making a magnificent park out of a waste area of drifting 
sand. The planting durmg the past 40 years furnishes the best record 
of the successful use of acacias in reclaiming sand dues that exists. 
At the present time there are superb thickets and copses of acacias, 
thoroughly established and naturalized, so that they require no culti- 
vation. Not only that; they are extending themselves fropi year to 
year, within a stone's throw of the Pacific Ocean, and fixing the va- 
grant sands. Further inland similar thickets are changing to acacia 
forest, capable of yielding firewood and timber. 

The planting began in 1870, and the stock used was chiefly for 
ornamental purposes. Trees from this first experiment are now stand- 
ing in the older portions of the park — magnificent specimens of A. 
melanoxylon and A. decurrens. But even with this earliest planta- 
tion, some were set out on the sand hills to the west, simply as an 
experiment. 

The westernmost 730 acres of this famous park consisted of great 
shifting dunes of sterile sea sand. The larger native growths were 
scattered evergreen scrub oaks and willows in the hollows between the 
barren sand hills. Often the dunes would drift over the mllows and 
oaks and kill them. The struggle of these plants is clearly showii by 
the fact that lupin roots have been traced downward for more than 25 
feet in the sands, while the roots of the willows have been followed 
for more than 100 feet from the main stems. 

While many of the original acacias have been removed for one 
cause or another, this still remains a wonderful object lesson in 
acacia planting. Some trees have been taken out in the necessity 
for thinnings ; others have had to give way to new driveways as they 
reclaimed the sands, thus making it possible to extend the cultivable 
portions of the park. The buildings for the Mdwinter Fair of 1893 
and the shelter tents for the homeless after the earthquake and fire 
of 1906 further diminrshed the thickets and groves, yet the arboretum 
contains the only California specimens known to the author of 
Acacia discolor, A. capensis, and A. coccinea. 

These complete and long-continued tests indicate that the shrubby 
Austrahan acacias will cover sand dunes rapidly and efficiently and 
will furnish firewood in from 8 to 10 years from seed. Wliile all 
this stock was nursery grown and transplanted, experiments in other 
places seem to indicate that seed can be sown directly on such sand 
slopes, and that the expensive nursery and transplanting practice, 



14 BULLETIN" 9, U. S. DEPABTMENT OF AGRICULJURE. 

while securing quicker results, is not really necessary. It should be 
kept in niind, too, that these plantations were not irrigated, and 
were left to shift for themselves. 

At the very shores of the Pacific, south of the famous Cliff House, 
a place famiUar to thousands of tourists, there are large low growths 
of acacia and albizzia, so close to the beach that the spray from the 
winter waves dashes over them. They are from 4 to 8 feet high, 
with close-matted roots and tops, which bind the sands and com- 
pletely cover them. They are from 6 to 16 years old, and their 
stems are from 1 to 2 inclies through. The albizzias begin to flower 
in November, and self-sown seedUngs are numerous. They seem 
better able than the acacias to extend their foothold on the beach's 
extreme verge. The acacias bloom in February; they make few 
seeds in such an exposed situation, though fartlier inland they seed 
well. 

A little farther east and more inland, at about a thousand feet from the 
ocean, are more acacias, jirincipally Acacia longifolia, growing among 
and over the sand liills, and tliougli these are no older than the beach 
thickets they are from 8 to 12 feet high, because they are more 
sheltered and in less sahne soil and atmosphere. A very large area 
which was hopelessly barren has been rendered attractive by the 
acacia copses. There are a few sand willows and pines, but the bulk 
of the growth is of planted and self-sown acacias. 

Still farther east, nearly haK a mile from the ocean, but still on 
land which was formerly sand dunes, the acacias are somewhat older 
and give each other good protection. These are from 20 to 30 feet 
high, with stems from 10 to 18 inches in diameter. Like all the others 
in the sand liills, these trees never received any artificial ap])lication 
of water. They were set out during the rainy season from seed boxes 
when only a few months old, and were then left to fight their own 
battles. In many cases the little trees grew from 3 to 5 feet during 
the first spring. 

In November some of the acacias on the sunny sides of the dunes 
show bloom, and by the middle of January the whole expanse is 
golden with blossoms. This is two weeks ahead of the same species 
on the beach. 

The mixed plantations along railroad cuts in and near Golden Gate 
Park and in some of the older groves where good soil has been spread 
over the sand are now large and thrifty, fairly deserving the name 
forests. Individual specimens are 24 inches in diameter and are 
fit for timber. 

There has always been a struggle between the sand and the vege- 
tation, though in the end the acacias seem to be able to fix the soil, 
even though they have been temporarily killed back. Where the 



AN ECONOMIC STUDY OF ACACIAS. 15 

sand has drifted in over the tops the trees have sprouted again from 
below, and have formed impassable thickets. These close clumps 
on pure sand do not seem able to grow higher than from 20 to 25 
feet, but even this far surpasses the native scrub oak and willow. 
As the park reclamation is made complete, however, and richer soil 
spread, out on the sand, Acacia decurrens and other large species 
immediately begin to grow sturdily, and age for age are as handsome 
and thrifty as those anywhere else in California. 

The especial value of these experiments upon California sand 
dunes is the proof it gives that useful and ornamental plantations can 
be made in such places. The natural desirability of residences on or 
near the seashore is greatly increased if such homes can be sheltered 
by groves and thickets. Acacias not only furnish these groves, but 
help to retain the soil, furnish firewood, and, in the end, timber and 
tanbark. Nearly all of the acacias are beautiful in leaf and flower 
and graceful m their growth. Along the California coast, therefore, 
as on that of the Mediterranean, they should be extensively planted. 

Correlating the Golden Gate Park and the South African experi- 
ments, species which seem most desirable for American plantations, 
for rapid reclamation and maxunum profit are -4.. pycnantha, decurrens, 
leiopliylla, and longifolia sown in combination with shrubby species 
which will give way when the sands are fixed and forest conditions 
established. The shrubby form oi A. longifolia is the variety sophorse, 
the spreading coast wattle; the tall form which might follow this is 
the Syllney golden wattle, the bark of which yields from 15 to 20 per 
cent of tannin, used chiefly for sheepskins. When the sand-dune 
area has become well covered with A. pycnantha and A. decurrens it 
is a tanbark proposition. If the object is mainly shelter and beauty, 
with the production of some tanbark as a secondary consideration, 
the final species would well he A. cyanophylla (blue wattle), A. decurrens 
var. mollis and A. haileyana, as well as A. pycnantha. All these thrive 
near the seashore and on light soils. Acacia longifolia, cyanophylla, 
and pycnantha are the best ones for inland localities up to an eleva- 
tion of from 2,000 to 2,500 feet m southern California, though the 
amount of frost rather than the elevation furnishes the deciding 
factor. In this list, all except A. haileyana yield tanbark. A purely 
ornamental plantation on the seacoast niight mclude several hundred 
species, and would be exceedingly attractive. 

Because of its rapid growth in California and its value as a shelter 
and a sand binder Albizzia lophantha should be extensively planted. 
It is one of the best species for obtaining a quick sand cover, and 
reproduces itself faster than any of the true acacias. It is particu- 
larly advantageous as the extieme advance guard of acacia plan- 
tations nearest to the shore. 



16 BULLETIN 9, U. S. DEPARTMENT OF AGRICULTUEE. 

ACACIAS FOR TANBARK. 

At the present time the chief commercial value of acacias seems to 
be for tanbark, although even with the tanbark species there are 
important by-products. The tanbark industry is bound to mcrease 
in importance; tanners are searching farther and farther for the 
materials they need, especially since, for the treatment of heavy, 
high-grade leathers, no real substitutes for the best vegetable tans 
have yet been discovered. 

Important Tanbark Species. 

All of the leading tanbark acacias are from Australia and are gen- 
erally known as wattles. This term is of local origin. Early settlers 
in the Australian bush made huts by weaving or wattling green 
branches together, and since acacias were most often used the name 
wattle has since been applied to the strong-growing species. In his 
time Von Mueller designated only five acacias as wattles, though he 
names many others as yielding tanbark. Dr. Maiden applies the 
term to more than 30 species whose bark he has tested. It is evident, 
however, that while many will yield bark worth using, when the tree is 
cut for tunber (this is true of all the more valuable timber species) only 
A. pycnantha and the best varieties of A. decurrens justify planting for 
tanbark alone. Acacia decurrens mollis and decurrens normalis are 
the largest and best of the decurrens fonns, and are stronger growing 
trees than A. pycnantha, but the latter yields the richer bark. These 
trees, then, are all that are worth serious attention for tannic acid. 
Acacia melanoxylon, decurrens, dealhata, longifolia, and others whose 
timber is of first importance yield tanbark only as a by-product. 

The two decurrens varieties (Acacia decurrens mollis and A. decur- 
rens normalis) may be taken as the typical tanbark acacias. Von 
Mueller's statement in 1882 of the value of their bark can scarcely 
be improved upon: 

It varies in its content of tannin from 30 to 40 per cent in bark artificially dried. 
One and one-half pounds of the bark give 1 pound of the leather, while 5 pounds of 
English oak bark are requisite for the same result. Melbourne tanners consider a ton 
of black wattle bark sufficient to tan 25 or 30 hides; it is best adapted for sole leather 
and so-called "heavy" goods. 

Acacia Pycnantha. 

Acada pycnantha is now strongly recommended by all who have 
studied tanbark production from this genus. The Kew Bulletin of 
1893 especially urges the planting of .A. pycnantha. Naudin says tbat 
the bark of this species has been Imown to contain 46 per cent of 
tannic acid, and that ordinarily it yields from 35 to 40 per cent. 
According to Von Mueller it is "second perhaps only to Acacia 



Bui. 9, U. S. Dept. of Agriculture. 



Plate IV. 




Fig 1 -Drifting Sands Held in Place Along a Car Track by a Plantation of 

ALBIZZIA LOPHANTHA, NEAR THE CLIFF HOUSE, SAN FRANCISCO. 




Pir 2 -A Massed Planting of Acacia longifolia in the Reclaimed Portion of 

■^GOLDEN GATE PARK, SAN FRANCISCO. BLUE GUM, EUCALYPTUS GLOBULUS, AND 



GOLDE 

Monterey Cypress in the Background 



Bui. 9, U. S. Dept. of Agriculture. 



Plate V. 



•i%;:' 








^;i 




iirX- \ .T^ 



Fig. 1 .—Acacia lonqifolia from Self-Sown Seed, Berkeley, Cal. 




Fig. 2.— Young Growth Starting from a Broken and Scarred Trunk of Acacia 

DECURRENS MOLLIS, BERKELEY, CaL. 



Bui. 9, U. S. Dept. of Agriculture, 



Plate VI. 



-» '-«» 






f¥ „ 




=>2 



lij o 




<Q. 



Bui. 9, U. S. Dept. of Agricultur 



Plate VII. 




Fig. 1.— Tanbark Acacias of Santa Monica, 20 Years Old and from 30 to 40 
Feet High. Acacia decurrens mollis and decurrens dealbata. 




FiQ. 2.— Tanbark Acacias (decurrens mollis) at Berkeley, Cal. 



AX ECONOMIC STUDY OF ACACIAS. 17 

decurrens.m importance for its yield of tanner's bark; the quality of 
the latter {A. pycnantha) is sometimes even superior to that of the 
black wattle, but the yield is less." Dr. Maiden says it is ''one of the 
richest tanning barks in the world; a richer may exist, but I dg not 
knbw of i.t." The sample bark that he analyzed in 1880, by Low- 
en thal's improved process, showed tannic acid 46.47 per cent, extract 
74.07 per cent. This was, of course, an extremely rich 'sample. 
Thirteen samples from the Government farm at Bellair, South Aus- 
tralia, taken from trees at various ages and grown on different soils 
ranged from 28.5 to 38.5 per cent tannic acid and from 57.75 to 
68.35 per cent extract. The trees were from 3 to 7 years old; the 
soils were light and shallow and mostly on a bedrock of hard 
sandstone. 

This is the true goldep wattle of Von Mueller, and when in bloom 
It is strikingly attractive. It is considerably smaller than any of the 
A. decurrens forms; hence it may not yield as much bark per acre as 
Acana decurrens mollis. But the trees can be set closer together, 
and the quality of the product is unsurpassed. 

ACACIA DECURRENS DEALBATA. 

Good barks of Acacia decurrens dealbata, or silver wattle, contain 
about 25 per cent of tannic acid. In some situations it grows faster 
than the normal A. decurrens, and when full grown always forms a 
stately tree. It requires rich moist soil and a frostless locality On 
river banks m Australia it reaches a height of 150 feet; in California 
the largest recorded specimen is 90 feet high and 2* feet in diameter 
Several considerations militate somewhat against its plantijig In 
the first place, it will hardly pay to plant it where the more produc- 
tive A. pycnantJia and A. decurrens will thrive; and it is not frosthardy 
Ihe^root system of A. dealbata, like that of A. melanoxylon, is mainly 
at the surface, and the trees are easiiv blown over. 



ACACIA MELANOXYLON. 



The a].pearance of Acacia melanoxylon, the black wood of south- 
eastern Australia, is very different from that of the feather-leafed 
acacias. It belongs, with Acacia ImigifoUa, A. pycnantha, and most 

Z-lt\ !^ T '?'"'"'' ^"^ ^^' wonderful phyllodinous acacias. 
With these the true leaves are suppressed, or nearly so, and the flat- 
tened leaf-stalks (phyllodia) perfonii the functions of leaves. The 
first foliage from seedlings of any of these species are delicate, 
leathery, bipinnate leaves; but the leaf-stalk soon broadens, length- 
ens, and hardeais, finally changing to a leatherv phyllodium. Some- 
times a few of the true leaves wiU persist for a long time at the 

6746°— 13 3 



18 BULLETIN 9, U. S. DEPAKTMENT OF AGKICULTUKE. 

terminals of the former leaf-stalks, and occasionally they may show 
on the younger growth. 

The tree is less valuable for tannin than for timber; but a tree so 
large and rapid-growing, the bark of which has a 15 or 20 per cent 
tannin content, should not be neglected in calculations for tannin 
production, especially since the development of the manufacture of 
tannin acid extract. A. melanoxylon properly belongs to moist and 
not frosty situations, and its roots are surface feeders. When 3''oung 
it is particularly susceptible to drought, and will die on soil the least 
bit arid ; moreover, it succumbs readily to desiccating winds, such as 
the drying northers of California. Von Mueller reports it as being 
hardy (with some forms of A. decurrens) on the Isle of Arran, Scotland. 
This does not, however, prove the hardiness of the tree so much as 
it does the variation of local climatic conditions, since A. melanoxylon 
has been injured by frost (7° F.) at Chico, Cal. It is useless to plant 
it in arid uplands, but its resistance to trying city conditions and its 
power of utilizing sewage make it of value as a street tree. 

Tanbark Acacias Abroad, 
australia and new zealand. 

In Australia acacias have been utilized for tanbark for a long time, 
the natural supplies being drawn upon exhaustively and the artificial 
culture of acacias consequently neglected, since there was an abun- 
dance of tan-yielding species on hand. 

Some 35 years ago, however, Baron von Mueller called attention to 
the rapid depletion of the natural supply, and from that time a volu- 
minous and important official literature upon acacias and acacia cul- 
ture grew up. Since 1875 these reports have aroused general as well 
as local interest in the planting of the species for tanbark. 

The three earliest and most careful estimates of planting costs, 
based upon actual experiments in 1878, 1884, and 1889, give, respec- 
tively, the following figures : 

(1) Acacia decurrens, 100-acre basis, rented at $1.50 an acre a year, 
400 trees planted per acre: 

Aggregate sales of bark, first 8 years, 1,215 tons $23, 290 

Aggregate expenses, including interest 7, 270 

Profit 16,020 

(2) Acacia pycnantM, 100-acre basis, bought at $15 per acre; 1,200 
trees to the acre: 

Aggregate sales of bark, first 7 years, 500 tons $12, 000 

Aggregate expenditure, first 7 years, including interest 8, 700 

Profit ..<.... 3,300 



AN ECONOMIC STUDY OF ACACIAS. 19 

(3) Acacia pijenantha, 100-acre basis, sowed broadcast and thinned 

to 1,200 trees to the acre; land rented at 8 cents an acre a year, under 

the provisions of the wattle-culture act passed in Victoria Colony 

in 1889: 

Aggregate sales of bark, first 7 years, 642 tons $23, 120 

Aggregate expenditure, first 7 years, including interest 7, 360 

Profit 15,760 

While these estimates differ considerably, based as they are upon 
various crop prices, land values, production costs, and }aelds, they 
are still suggestive. In fact, the only point in common between the 
three plantations was that in each case there was good preparation 
of the soil and careful cultivation. 

The Queensland Agricultural Journal recently reported that in 
Auckland, Xew Zealand, an otherwise useless tract of land of about 
4,500 acres planted to Acacia decurrens gave the following results: 

Aggregate sales of bark, per acre, first 8 years $142 

Aggregate expenses, per acre, first 8 years 70 

Profit (not including 5 cents per acre per year, and not including intert 
est) 72 

In South Australia, on the unproductive "fern hUls" of white sand 
and on dry limestone ridges, acacias grow well. Such land can be 
rented at less than 4 cents per acre a year, and ought to yield from 
$70 to $80 per acre at the end of 8 or 9 years. Better soils w^ill give 
proportionately better yields, but the striking thing about the New 
Zealand and Australian reports is the unanimity of opinion as to the 
value of wattles upon poor soils. 

SOUTH AFRICA. 

Thirty years' experience with tanbark wattles in Cape Colony, 
Natal, and other places in South Africa has been quite as interesting 
as the experience with sand-binding acacias. 

Originally introducing Acacia saligna for tanbark. Cape Colony 
made strenuous efforts to plant large areas. In some districts mate- 
rial was needed for huts, fences, and fuel, and this made a demand for 
small stuff which would grow rapidly. This demand led to the plant- 
ing, in some instances, of as many as 20,000 acacias to the acre, the 
plantations being thinned out at the end of the fourth year and the 
wood and bark of the trees removed in thinning being sold. In some 
plantations trees were set in rows 4 feet apart or alternated with 
cluster pines. By 1890 about 150 tons of bark were marketed, and 
in 1891 nearly 2,500 tons, partly from government forests and partly 
from trees belonging to settlers. 

As soon as the superiority of other tanbark species was recognized, 
Acacia saligna was dropped and better species planted on an exten- 



20 BULLETIN 9, U, S. DEPARTMENT OF AGEICULTUEE. 

sive scale. In 1896, for example, 494,873 Acacia decurrens were set 
out in one of the Crown forests. At another place 10^ acres were 
sown broadcast with this species, and on one-half acre seed was 
drilled in. 

Tanbark acacias have been planted more or less extensively, espe- 
cially since the war in the Transvaal. The assistant conservator of 
the Transvaal forests published a full report on acacia culture in the 
Transvaal Agricultural Journal for January, 1910. In this he states 
that after extensive trials Acacia decurrens (varieties normalis and 
mollis or mollissima and Acacia cycnantlia) are found to be the best 
sort, with the decurrens iy^Q in the lead. Photograpliic illustrations 
in the report show dense, mature wattle plantations and also the pro- 
cesses of stripping and preparing the products for market. He states 
that wattles can be grown anywhere in the Transvaal, but most suc- 
cessfully at elevations of from 3,000 to 5,000 feet on the high plateaus, 
with a preference for eastern slopes. The most suitable soil is a light 
red or chocolate well-drained loam. The annual rainfall is from 30 
to 40 inches and there are no extreme frosts. Acacia culture is spoken 
of as a most promismg industry. 

NAT4L. 

Probably the most suggestive and interesting chapter in the liistory 
of commercial planting of acacias is furnished by the rise of the wattle 
industry in Natal during the past 30 years. The yield from culti- 
vated trees surpasses that which has been obtained from natural 
growth, the two leading forms of Acacia decurrens being the most val- 
uable kinds, with mollis as the hardier variety. In 1886 the acacia 
tanbark export was valued at $55. By 1902 the exports had risen 
to $370,000 worth, and this does not include any report of material 
used for local consumption. Several companies planted 3,000 acres 
and some are adding at the rate of a thousand acres a year. It is 
claimed for the industry that it yields a high rate of interest without 
high-priced management and utilizes soils unsuited to general cultiva- 
tion. In 1906 Natal had more than 30,000 acres in acacia plantations 
and at the present time this area is more than doubled. Mr. David 
G. Fairchild, in charge of Foreign Seed and Plant Introduction, 
United States Department of Agriculture, states that the black wattle 
most generally planted has been Acacia decurrens mollissima} He 
notes that a few years ago wattle bark reached the price of $82.79 a 
ton and this high price greatly stimulated planting. What is known 
as the Townhill plantation, 2,400 acres, situated 2,700 feet above sea 
level, was begun in 1892. The topography was rolling hills and the 
soil a light red loam with sand, gravel, and clay. The tract was 

1 Miscellaneous Papers, Bulletin 51, Bureau of Plant Industrj-, U.S. Department of Agricultiu-e. 



AN" ECONOMIC STUDY OF ACACIAS. 21 

grass covered and therefore required no clearing. Rows were marked 
at 12 feet apart and the seed was hilled 6 feet apart in the rows. 
Corn was grown between the ro\vs for the first two years in order that 
its }deld would help to reduce expenses. At 10 years old the trees 
were 10 inches in diameter. 

All the work on this 2,400 acres is done by 60 natives, who peel, 
cut, and dry the bark, strippuig it at any season that it wiU peel 
easily. They use drying sheds of galvanized iron, each one of which 
holds about 6 tons of bark. 

The gross receipts from 10-year-old trees at the price of $32 per ton, 
when Mr. Faii'child made the study, was from $161 to $193 ati acre. 
The operating cost for harvesting the product was $7.30 a ton or 
$43 an acre. The 10 years' care of the land, the cost of the land — 
in this case only from $5 to $6 an acre — and mterest were said to be 
covered by the sale of the wood for m'uie props, fuel, and small timber. 
No replantmg has been necessary, since thousands of seedlmgs come 
up and cover the ground. 

Another valuable publication on acacias in Natal has been fur- 
nished by Mr. T. R. Sims;^ but the most complete publication which 
covers the entii'e mdustry in 10 countries is the third edition of 
Dr. Maiden's '' Wattles and Wattle Barks." 

NORTH AFRICA. 

Johannes Paessler, of Levertechn, published in 1910 a paper on 
acacia bark grown m North Africa, in which he speaks of Acacia 
decurrens, decurrens mollis, decurrens dealhata, pycnantha, and j)^n~ 
ninervis. Accordmg to his report only the best species are planted 
and the tannin yield, which was less than 30 per cent, is now increas- 
ing. Acacia decurrens in German East Africa, at an elevation of from 
4,000 to 4,500 feet is ready for gathering at five j^ears, and yields a 
bark of higher tannm content than that from Natal. At Freiburg 
Station 260 bark samples were analyzed by the filter method since 
1901, with the folio wmg averages: 

Per cent. 

Tannins 33 

Nontannins 8. 5 

Insolubles 43 

Water 14. 5 

There is a smaller proportion of nontannins to tannins m acacias 
than m the domestic barks, such as oaks. The sugar content is very 
low, which gives the acacias only slight acid-formmg power. Ground 
acacia bark, accordmg to this report, in Germany in 1910 cost $55 
a ton, which makes the tan worth about 8^ cents a pound. 

» "Tree Planting in Natal," Chapter 9: " The Black Wattle Industry," Bulletin 7 of the Natal Depart- 
ment of Agriculture, Pietermaritzburg, 1905. 



22 BULLETIN 9, U. S. DEPARTMENT OF AGRICULTURE. 



Prof. Jared C. Smith has made a full and careful report of experi- 
ments with black wattles in Hawaii.^ In this he states that acacias 
have been grown in the Hawaiian Islands for about 40 years, thrivmg 
on heavy soils with a rainfall of from 80 to 150 inches. The remark- 
able fact m connection with this exceedingly heavy rainfall is the 
adaptability of the acacias to various conditions from drought to 
deluge, and pomts to their possible use in such locations as the 
Colorado River bottoms and along the Gulf coast. 

Six acres of 13-year-old trees yielded $254.84 per acre. The bark 
brought about $139 (5.9 tons at $23.31 per ton). The wood sold for 
fuel yielded about $114. 

According to Mr. Smith, one man with good tools and a team can 
take care of 250 acres of black wattles with ease when it has once 
been sown and thmned. "One pound of good seed should plant 
10 acres." This illustrates scientific progress, smce many planters 
have been in the habit of sowing 5 or 10 pounds to the acre. Yet 
Acacia fycTiantha has about 23,800 seeds to the pound; A. normalis, 
about 28,500, and mollis 38,500. The present Australian practice is 
to sow from one-third of a pound to a pound of seed an acre, but since 
1,200 trees is an abundant stand and 800 is better, a pound of good 
seed should sow 10 or more acres. In the famous Tantalus acacia 
plantation m Hawaii, the trees of 13 years vary from 6 to 18 inches. 
A 10-year-old tree would yield 100 pounds of green bark, which is 
equal to 50 pounds dry. The best trees yield as much as 200 pounds. 

Tanbark Acacias in California. 

While there are no commercial plantations of tanbark acacias in 
the United States, the leading tanbark acacias have long been grown 
at the California Experiment Station at Berkeley and at various sub- 
stations. Their product has been analyzed and compared with that 
from the California oaks and from canaigre (Rumex hymenosephalus) . 
In the bulletins of the California Experiment Station and of the 
Federal Forest Service ^ attention has been called to the rapid disap- 
pearance of California tanbark oak (Quercus densijlora), the tannm 
from which has given high reputation to California-tanned heavy 
leathers. The constantly increasing cost of the bark'has been noted 
and at the same time the deterioration of its quality, smce mere 
bushes and saplings are now being stripped for the thin young bark, 
incomparably inferior to the old thick bark from the boles of matm-e 
trees. The necessity of securing a supplement to or substitute for 

' Bulletin 11, Hawaiian Experiment Station, 1906, "The Black "Wattle in Hawaii." 
2 Bulletin 75, Forest Service, U. S. Department of Agriculture, California Tanbark Oak, by Willis Linn 
Jepson, issued Sept. 20, 1911. 



AN ECONOMIC STUDY OF ACACIAS. 23 

this source of tanning material has been recognized for some time; 
the planting of wattles would seem to offer a solution for the difficulty. 

POSSIBILITIES OF GROWTH. 

There are enough trees in California to furnish seed ; and the growth 
of individual trees has already demonstrated the fact that tanbark 
acacias should be successful over large areas. On the Pacific coast 
and in the Southwest there are many districts well adapted to tan- 
pelding acacias; and there should be a market not only for the bark 
but for fuel wood after the bark is removed. Even where isolated 
trees suffer from frost, groves of trees sheltering each other will not be 
subject to the same damage. Acacia pycnantha, even when small, 
has withstood the winters of Cholame Valley, Monterey Comity, in a 
district where peach, cherry, and grape crops have been lost through 
late frosts. 

While the amount of rainfall which acacias require seems not to 
have been determined, it is generally assumed that 16 inches a year 
is the minimum for Acacia decurrens. Yet deep-rooted saplings will 
thrive on much less. The reports of the University of California 
show that in the drought years of 1897, 1898, and 1899 acacias of 
the leading tanbark species grew well with rainfall of from 4.8 to 8 
inches. In Los Angeles Comity young trees set out in the spring of 
1897, and thus subjected to tliree successive drought seasons, made 
growths of from 4 to 6 feet in height a year, and in 1911 were 2 feet 
in diameter. These and other instances justify the belief that some 
of the best Australian acacias will tlirive in America mider almost 
desert conditions. If they can be made to supplant large areas of 
chaparral they will maintain a protective covering for the soil and 
produce in addition a profitable crop. 

The increasing demand for tanbark ought to direct attention to 
these drought-enduring wattles. In California the native oak has 
advanced in price from $6 per ton in 1870 to $48 at the present time. 
Bark cutters are now forced to seek the most remote and rugged 
canyons in Mendocino, Humboldt, and Del Norte Counties, and some- 
times carry out the bark on pack mules. In the Mendocino forests, 
once thought to furnish a practically inexhaustible resource, the 
writer has seen the bark cutters strippmg trees only 3 inches in 
diameter. 

California has a large investment in the tannuig industry, and 
California leathers are shipped to all parts of the world, so that the 
disappearance of the main source of tamiiii supply becomes a serious 
problem. 

It should be possible to produce wattle bark for market on low- 
priced land from cheap home-grown seed. While it is useless to 



24 BULLETIN 9, U. S. DEPARTMENT OF AGEICULTUKE. 

expect to rent land in America at the Australian price of 4 cents ar 
acre a year, there is nevertheless cheap and suitable land in Cali- 
fornia and the Southwest. 

TANNIN CONTENT OF CALIFORNIA BARKS. 

The first acacia barks analyzed by the University of California 
were those of Acacia decurrens mollis, A. decurrens dealbata, and A 
pycnantha. In the report upon these barks ^ it was shown that the 
California-grown bark of mollis was twice as thick as that of dealbaU 
of the same age and that it yielded about twice as high a percentage 
of tannin. This agrees very nearly with comparisons made upoi 
barks grown in Australia and in Algeria. The actual tamiin contents 
of these three barks grown at Berkeley were as follows: 

Per cent. 

Acacia decurrens mollis 48. 6 

Acacia decurrens dealbata 24. 8 

Acacia pycnantha 46. 8 

Dr. HUgard states that these tannm determinations were mad( 
by the permanganate method, repeatedly checked by the gelatin oi 
hide-strapped method, with but triflmg differences in the results, sc 
that the figures fairly represent what hides will take up. 

One of the trees, 13 years old when cut for these experiments, was 
12 inches in diameter at 3 feet above the ground, and 40 feet high 

It will be observed of these analyses that California-grown^. pi/c- 
nantlia bark, contrary to Australian experience, did not exceed mollit 
in richness of tannin 'content. Later analyses seem to confirm this 
general fact : That^. decurrens normalis and mollis are proportionatelj 
richer m tannin when grown in California than when grown ir 
Australia. As yet, however, the quantity of bark which has beer 
produced is not sufficient to settle this mteresting and iniportani 
point, though everything points to the desirability of both of thes( 
forms of Acacia decurrens for planting m California, particularly ii 
the Coast Range, where the bark so far tested has been grown. 

Another report - gives some interesting statistics about the planta- 
tion at Santa Monica, which has been under charge of the Universit} 
of California since 1894. This report states that Acacia decurreni 
and A. pycnxintha, 25 months from seed (20 months planted m the 
field), have grown twice as rapidly as the same species mentioned ir 
Australian reports. Many trees of this age had attained a height ol 
16 feet and the very poorest were 2 inches m diameter and 9 feel 
high. Mr. Lyon estimated that at 4 years of age such a plantatior 
would yield a crop of bark equal to that of 7 or 8 year old Australia! 
groves; that is, from 80 to 90 pounds of bark to a tree. 

■ Report of Dr. IlUgard, Jan. 23, 1884. 

2 Third Annual Report of the First Board of Forestry of California; Chapter on Acacias, by W. G 
Lyon, State Forester, 1890. 



Bui. 9, U. S, Dept. of Agriculture. 



Plate VI!1 




<0 




Bui. 9, U. S. Dept. of Agriculture. 



Plate IX. 




°c3 



4 


^M 




i' . . «c .#iB> ■ 






Ih 


1 :•■?!■■ , :--'^^i^,..,^ 


T^W^^ 


f- ^^^-^-^hmmU 


(■if-. V, >■ 



50 

O uJ 



I- < 

P 

h- 
I 



AN ECONOMIC STUDY OP ACACIAS, 



25 



There are reports of trees of Acacia decurrens mollis in southern 
California which when 4 years old were 30 feet high and 8 inches 
in diameter. 

A complete analysis of the tanbarks grown at Santa Monica 
Forest Station, made in Jmie, 1898, by Mr. George Colby, of the 
California Experiment Station, gives the following results: 



Water in 


Tannin in 


air-dried 


air-dried 


bark. 


bark. 


Per cent. 


Per cent. 


6.53 


42.48 


8.28 


36.57 


5.28 


31.35 


7.60 


45. 98 


8.08 


42.98 


7.89 


32.37 


9.32 


41.80 


8.67 


38.66 


7.10 


47.02 



Water-free 
substance. 



Acacia decurrens normalis: 

Bark, main tree 

Bark, branches 

Bark, large roots 

Acacia decurrens mollis: 

Bark, main tree 

Bark, branches 

Bark, large roots 

Acacia pycnantha: 

Bark, main tree 

Bark, branches 

Bark, large roots 



Per cent. 
45.83 
39.98 
33.10 

49.76 
46.66 
35. 18 

46.09 
42.34 
50.58 



Two points are brought out by these analyses: Acacia 'pycnantha 
alone showed a higher proportion of tannm than a bark with a large 
root, although this fact is likely to be true of the various forms of 
Acacia decurrens. The superior value of Acacia decurrens mollis is 
plain. All of these barks gave good results in practical tests by 
tanners. It should be stated that these results were not obtained 
from conmiercial plantations, and that notwithstanditig the figures 
which were presented so many years ago by the University of Cali- 
fornia, no commercial plantations were set out. The principal reason 
for this was that at that time the demand for tanbark in California 
was sufficiently supplied by tanbark oak, which was then abundant; 
moreover, public. attention had not been then directed to the possi- 
bilities of forest planting for timber, tanbark, and other products. 

ACACIAS FOR TIMBER. 

Throughout the world there is evidently an increasing demand for 
hardwoods. In the eastern United States, which probably furnished 
the best supply of hardwood lumber that has ever been known, the 
dmimution of the supply has already caused readjustments in several 
industries which have depended upon it.^ The foresters of South 
Africa, Algeria, and Australia are planting tons of acorns to gi'ow 
future hardwood forests. California m particular, rich in conifers, 
has no hardwoods of commercial importance, and the introduced 
eucalypts present many difficulties in utilization. 

Principal Timber Species. 

Many of the acacias furnish useful and valuable timber and are not 
only beautiful in grain but durable in contact with the ground. Even 



1 Circular 116, Forest Service, U. S. Department of Agriculture, the Waning Hardwood Supply. 



26 BULLETIN 9, U. S. DEPARTMENT OF AGRICULTURE. 

the smaller species have high value for tool handles, for furniture, and 
for various other useful and ornamental objects. Some of the best 
species yield very hard, heavy, close-grained, tough timber that is 
fauiy comparable to walnut and rosewood. 

Acacia melanoxylon. — Wherever it thrives Acacia melanoxylon is 
considered the most valuable of the timber acacias. The tree grows 
very rapidly and reaches a height of from 80 to 90 feet and a diameter 
of 3 feet. Von Mueller reports its strength as sui'passmg that of 
kauri and approaching the best American white oak. In his experi- 
ments a weight of 2,296 pounds is required to break a piece of Acacia 
melanoxylon 2 feet long and 2 uiches square, supported at the ends. 
The Victorian Timber Board, in 1884, found that 956 pounds were 
required to break test pieces 1^ mches and 6 feet between bearmgs. 
This wood averaged 53 pounds per cubic foot, but its more usual 
weight is from 41 to 48 pounds. The tensile strength of good sam- 
ples is reported by Mr. Campbell at an average of 27,500 pounds per 
square mch.^ The Kew BuUetm for May, 1899, states that the timber 
of Acacia melanoxylon is somid and easily worked; that its prevailing 
color is brownish, striped with red and light golden, which made an 
"exceedmgly beautiful" combination m the best specimens. The 
report adds that such a wood may be used to advantage in place of the 
best Honduran mahogany, and that some lots, while less ornamental, 
■'are excellent for high-class turnery." Maiden says: 

Hard and close-grained; much valued for furniture, picture frames, cabinetwork, 
fencing, bridges, railway and other carriages, boat building, tool handles, gunstocks, 
naves of wheels, crutches, parts of organs, pianofortes, billiard tables, etc.; almost 
equal to American walnut; excellent wood for liandling under steam; largely used 
for oil casks. 

It is also used for oars, buggy shafts, bookcases, tables, and cabmet- 
work of various kinds. 

Growth notes on Acacia melanoxylon in California show clearly its 
importance as a timber species. About a hundred tree measurements 
in different portions of the State, from Shasta south to San Diego, 
taken at various times between January, 1910, and June 1, 1913, 
show that on average soils, with an annual rainfall of from 15 to 30 
inches, and without irrigation, trees 20 years old average 40 feet in 
height, with a stem diameter of 18 inches. 

Some of the single measurements of older trees are as foUows: 

At Hotel Del Monte, Monterey, a tree 30 years old measured in 
May, 1913: Height, 70 feet; diameter at 4 feet from the ground, 
2 feet 8.4 inches. At Golden Gate Park, San Francisco, a tree 

35 years old, in ahnost pure sand, measured winter of 1912-13: 
Height, 60 feet; diameter, 4 feet from the ground, 2 feet. Another, 

36 years old, on better soil: Height, 75 feet; diameter, 4 feet from 

1 Proceedings of the Royal Society of Victoria, 1879. 



AN ECONOMIC STUDY OP ACACIAS. 27 

ground, 2 feet 8 inches. At Niles, a tree 46 years old, on side valley 
soil, 76 feet above San Francisco Bay, top broken off at height of 
65 feet, though the tree had been about 80 feet high, diameter 2 feet 
6 inches. Near Alvarado, a tree 45 years old, on rich soil, 85 feet 
high, diameter, breast high, 3 feet 9 inches. 

All portions of the Sacramento and San Joaquin Valleys appear 
well adapted to the growth of Acacia melanoxylon. At the Chico 
forestry station and elsewhere it showed no injury, except to the 
young tips of the top branches, during the low temperature of the 
coldest seasons between 1890 and 1913 (16°, 14°, and 12°). Large 
eucalypts were killed to the ground by these frosts. 

The bark of this species yields about 11 per cent of tannic acid, 
which could be utilized profitably when the timber is cut by con- 
centrating it in the form of an extract. The inner bark, as with 
some other acacias, yields a valuable bast or fiber material. 

Acacia decurrens group. — There is little difference in the woods of 
the three leading varieties of the Acacia decurrens group (normalis, 
mollis, and dealhata), but the last two grow more rapidly and attain 
the larger size. Dealhata trees have been measured and found to be 
100 feet high and 4 feet in stem diameter. This variety has been 
naturalized in southern India since 1840 and extended over a large 
area. The tunber of all three varieties is moderately hard, light 
brown in color, easUy worked, and strong; it is used by coopers and 
house builders; it is valuable for posts, for rustic work, for mine 
props under ground, and for fuel. Its weight is about 47 pounds to 
the cubic foot. 

Acacia decurrens normalis and mollis are more generally planted 
than dealhata. Von Mueller gives the weight of their timber at from 
45 to 48 pounds per cubic foot. Maiden reports that three slabs of 
normalis at the Technological Museum, seasoned for more than 
25 years, weighed, respectively, 52, 53, and nearly 63 pounds per cubic 
foot. 

Other timber species. — Many other species of acacia yield valuable 
timber. Of those listed, all have been grown in California. 

Acacia acuminata. — Stem diameter, 12 inches. Wood strong and 
very hard, red-brown in color, and durable. Has a raspberry-like 
scent. 

Acacia aneura. — Stem diameter, 10 to 12 inches. Exceedingly'- 
hard and strong wood of a dark-brown color. 

Acacia arahica. — Stem diameter of 2 feet. Wood used for boats, 
water wheels, and many implements, on account of its strength and 
durability. The tanbark is a by-product of this species. (See pi. II.) 

Acacia armata. — Shrub or small tree. Wood beautifully grained 
and durable. 



28 BULLETIN 9, U. S. DEPARTMENT OP AGRICULTURE. 

Acacia aulacocarpa. — Wood heavy, hard, tough, light red. A 
cabinet wood. 

Acacia hidwilli. — Stem diameter, 18 inches. Timber hard. Takes 
a good polish. 

Acacia hinervata. — Stem diameter, 12 inches. Wood close-grained, 
tough, light, called ''hickory." Used for ax helves. 

Acacia cunninghami. — Stem diameter, 12 inches. A dark-colored 
and heavy cabinet wood. 

Acacia doratoxylon.— Stem, diameter, 12 inches. Wood hard, 
tough, heavy, durable; very useful timber for buggies, whiffletrees, 
wagon poles, and furniture. 

Acacia falcata. — Stem diameter to 12 inches. Spoken of as another 
hickory. Wood heavy, hard, and tough; yellow and light brown; 
easily bent into sharp curves by carriage makers. Used also for 
stock-whip handles. 

Acacia farnesiana. — Stem diameter m some regions 6 inches. More 
valuable for its perfume-yieldmg flowers. A native of both hemi- 
spheres. Wood close, heavy; much used in India for ship knees and 
tent pegs. 

Acacia glaucescens. — Stem diameter 18 inches. Wood dark, re- 
semblmg rosewood, fragrant and close-grained; used by cabinet- 
makers and for tool handles. 

Acacia Tiarpophylla. — Stem diameter 1 8 to 24 inches. Wood brown, 
hard, heavy, elastic, straight-grained; has the fragrance of violets; 
much used for turnery; lasts many years m the ground. 

Acacia homalopliylla. — Stem diameter 1 foot. Wood hard, durable, 
and' heavy (specific gravity 1.124), very fragrant; used for fancy 
articles, cabinet work, and tobacco pipes. 

Acacia implexa. — Stem diameter 12 inches. The wood resembles 
that of Acacia melanoxylon, and is used for cogwheels and wagon hubs. 

Acacia longifolia and its varieties have stem diameters of 9 to 12 
inches. The wood is white, yellow, and brown in color, light, tough, 
hard; used for handles of axes and other tools. A. longifolia and its 
varieties are the most valuable among the sand-buidmg species. 

Acacia macradenia. — Stem diameter 12 mches. Wood strong, 
hard, and blackish. Takes a ftne polish. 

Acacia neriifolia. — Stem diameter 12 inches. Wood light yellow 
and dark brown; handsome, close-gramed, durable; used in cabinet 
work. 

Acacia pendula. — Stem diameter 12 inches. Wood very hard, close- 
grained, richly marked, dark in color, very fragrant; used for veneers 
and fancy cabinet work. 

Acacia pycnantha. — Stem diameter 9 mches. Wood very tough, 
weighs about 51 pounds to the cubic foot; used for staves, bobbins, 
and various articles of turnery. 



AN ECONOMIC STUDY OF ACACIAS. 29 

Acacia saZiarwi.— Stem diameter 15 inches; wood heavy, hand- 
some, dark bromi in color; weight of cubic foot 47 pomids; takes a 
high pohsh; much used for fui'niture. 

Acacia stenoi)liylla.—Stem diameter 20 mches. Wood very solid, 
close-grained, dark; takes a superior polish. Is called ''honwood," 
and is much used by cabmetmakcrs. 

Acacia suh-porosa.— Stem diameter 18 mches. Wood extremely 
tough and elastic; used for wagon poles, tool handles, gunstocks; also 
for spars of coasting vessels. 

Acacia Tcoa, of the Hawaiian Islands, has a stem diameter sometimes 
2 or 3 feet and is considered the best timber tree of the islands. Its 
wood is easy to work, hard, handsome, hi great demand for furniture, 
boats, and buildmg generally. It grows at an elevation of 4,000 feet 
above the ocean. The few remaming forests of this acacia should be 
protected and young plantations established to supply future needs. 
The tree has not yet been sufficiently tested in California. 

Acacia catecliu. — An even more valuable acacia is Acacia catechu of 
India . Stem diameter 2 feet . The heart wood , which is more durable 
than teak, is not attacked by insects. The weight of this timber is 
70 pounds per cubic foot, and it is used for pestles, crushers, rollers, 
and all sorts of wheelwrights' work. 

Besides these 25 species there are about 20 more which have not 
yet been tested m the United States, but whose wood is higlily valued 
m their native comitries for beauty or durability. 

Timber Acacias in California. 

Few of the trees which have been cut ui California for wood speci- 
mens have been more than 20 years old, nor have they had diameters 
greater than 18 mches. Larger trees are usually so ornamental that 
owners dislike to cut them. But these older and larger trees would 
show a better quality of timber. Another thing that should be taken 
into consideration is that none of the timber species have been grown 
in California under forest conditions. The specimens, in Hough's 
"American Woods" were grown in Akmeda County as park trees. 
In California, Acacia melanoxylon, the best of the timber acacias, has 
made a diameter growth of 18 uiches in as many years, and trees 25 
years of age attam the height of 60 feet and a diameter, in some few 
cases, of as much as 30 uiches. It is often planted as a street tree, 
and its ability to thrive near gas works and manufacturmg establish- 
ments, where nearly every other species of tree wiU perish, has already 
been commented upon. In Shasta and Amador Counties it has been 
noted that this acacia is markedly resistant to the fumes of copper 
smelting. In Oakland there are good specimens thrivmg on refuse 
dumps and in sewage. It will stand much surplus water, alkali, and 



30 BULLETIN 9, V. S. DEPARTMENT OF AGRICULTURE. 

sea salt. It is, however, not particularly frost hardy and is a tree for 
low, moist situations. 

It has one great advantage for forest management as a timber 
tree, and that is its power of i^eproduction over large areas from root 
suckers. Wlien a tree is cut down many sucli suckers sprmg up, 
even at a distance of from 30 to 40 feet from the parent stem, and- 
these eventually make sturdy trees. 

Acacia farnesiana was found at some of the California missions 
when the Americans came from the East and while it is not a large 
tree it should be valuable in California not only for its timber but 
for its perfume. Koa has not been sufficiently tested as yet in Cali- 
fornia, but its record in Hawaii points to great usefuhiess if it can be 
grown in commercial plantations. 

Nearly all of the hardwood required by the makere of agricultural 
Implements, wagons, carriages, railway coaches, street care, furni- 
ture, and cabinets, or used in the interior finish of houses and boats 
is imported into California and becomes year by year more costly 
and harder to obtain. The eucalypts, because of the difficulties of 
seasoning and working, are not filling the bill and the acacias may 
be exj^ected to help out considerably. 

other economic uses of acacias. 

Forage. 

The acacias as legumes have value as browse for wild and domestic 
animals. Those which contain a large proportion of tannin are, of 
course, not particularly relished by animals, but since the tannin 
content of the different species varies greatly, there are a number 
which do not have this drawback. In the great African and Asiatic 
deserts the leaves and young slioots of acacias form the principal 
browse of goats and camels. In Australia certain species are of con- 
siderable value for cattle, sheep; and other live stock. Shice some 
of the most useful forage acacias are also valuable for the fi_xation 
of drifting 'sands, seacoast thickets of these shrubs have a double 
economic value. 

The Australian ''scrub," locally known as "myall" and "mulga," 
consists of some 30 species of acacia, many of which display great 
drought-resisting qualities. Tlie four best forage species, in tlie 
opinion of Dr. Maiden, are Acacia aneura, A. doratoxylon, A. pendula, 
and A. saligna. To these might be added ATbizzia lophaniha, still 
catalogued by many California nurserymen as an acacia, which is 
particularly well adapted to seacoast conditions. 

Australian cattlemen say that saltbusli {Atriplex semihaccata) and 
myall make the best beef products on that contment. The best 



AN ECONOMIC STUDY OF ACACIAS. 31 

myalls thrive in California, especially on the sand hills, where they 
endure hard conditions. They would succeed on the Carissa Plams 
of San Luis Obispo and on the west side of the San Joaquin Valley. 

In some parts of California albizzias have become naturalized, 
have fixed the sand, furnish forage, and still continue to extend them- 
selves. On the sand dunes about a mile north of Morro Rock, San 
Luis Obispo County, ATbizzia lophantha, seK-seeded from a few door- 
yard trees 45 years ago, has gradually extended over about 50 acr^s. 
Each plant was browsed down to a mere green mat, which, like 
Thoreau's famous wild apple tree, finally become so wide across that 
the enemy could not bite off the central shoot, which tlien took heart 
of grace, grew high, became a tree, and seeded a new area. 

The adaptability of these forage-yielding acacias and albizzia to 
the deserts of Mojave and Colorado can be determined, of course, 
only by actual trials. But it is not unreasonable to hope that several 
such exotic species may hold the soil and furnish forage at the same 
time. 

In planting care should be taken to adhere closely to the few species 
which have been mentioned as valuable for forage, because some of 
the acacias are poisonous and sheep and cattle have been killed by 
eatmg the green buds. 

Shelter Belts. 

In all regions of brisk wmds and a high rate .of evaporation shelter 
belts are necessary to successful agriculture. In New Zealand the 
larger acacias are generally preferred to eucalypts for shelter-belt 
planting about orchards and fields; they take less from the soil, and 
in consequence crops can be grown closer to them. Acacia decurrens 
in its several varieties is best suited for this purpose, the seed to be 
sown where it is desired that the trees shall stand. 

Some of the smaller acacias fonn excellent hedges and barriers, 
requiring almost no pruning and no UTigation. There are about 40 
species well adapted to hedge purposes, and theii" local names testify 
to their eft'ectiveness — ''wait a bit," "dead finish," and ''kangaroo 
thorn." Acacia armata is well adapted to the coast districts, and 
while it is graceful and seemingly hannless it constitutes an impene- 
trable barrier. Acacia furox is a South African species which forms 
an especially good hedge. Acacia arahica forms large, strong bar- 
riers. Even the thornless and very ornamental acacias can be 
grown close to the ground and become protective barriers as well as 
attractive masses of bloom in their flow^nng season. The fragrant 
Acacia fame siana is often used for hedges, and Acacia cultriformis, 
A. cyanophylla, and A. baileyana are beautiful specimens for large 
barriers. 



32 BULLETIN 0, U. S. DEPAKTMENT OF AGRICULTURE. 

Gum Products. 

Several species of acacia already naturalized in America yield 
substances of great economic value, although in this country they 
are not as yet commercially utilized. 

One of the most important of these substances is lac, the product 
of an insect (Tacharia lacca) of the coccid family, which feeds on 
the juices of many host plants and especially on certain acacias. 
Lac culture is a large and profitable industry in sevoral countries 
and there is an increasing demand for the product. The literature 
of the industry is voluminous, particularly in the forest publica- 
tions of the Government of India/ where Acacia catechu and A. arahica 
are cultivated as hosts for the lac insect. Acacia farnesiana, per- 
haps more valuable for perfumeg, is also a lac-yielding species, as is 
the American Acacia greggi of Arizona. Since the value of the lac 
product on various species differs greatly, there is room for wide 
experimentation with those grown in America ; it is generally consid- 
ered, however, that Acacia catechu, the "kair tree" of India, is one 
of the best. 

Gum arahic. — Any mention of vegetable gums immediately brings 
to mind the wddely known gum arable, derived from Acacia arahica 
as the type, but yielded also by a number of Asiatic and African desert 
species, aU of which thrive in the warmer parts of the United States, 
and growing where the date palm has been successfully introduced, 
but requiring much less moisture. They are strongly alkali resistant 
and are adapted to true desert conditions. They should prove of 
value, therefore, in southern California, Arizona, and New Mexico. 
The more valuable gums used in medicine and in various arts and 
industries come from the Acacia arabica, A. Senegal, A. suma, A. verek, 
A. farnesiana, A. stenocarpa, A. gummifera, A. etbaica and others. 
The yield is variously graded and is marked under several trade 
names. Single trees will flow each year from a few ounces to a few 
pounds of gum, and the bleeding process can be continued for many 
years without harm to the plant. 

Many other gums are yielded by acacias, some of them highly 
astringent. Cutch, a product of Acacia catechu, is in constant demand 
and reaches market m several forms, as crystals found in the wood 
and as a gum, both pale and dark. 

The cheaper grades of gum are yielded niainly by the Australian 
acacias and are in general use. All of the decurrens varieties of 
tanbark acacias yield conmiercial gums in large quantities, known 
specifically as wattle gums and used as a size for leather, as a sub- 
stitute for isinglass, and for many other industrial purposes. Acacia 
hinervata, A, pendula, A. glaucescens, A. retinoides, A. homalopkylla^ 

1 In this connection there is a suggestive paper on the propagation and collection of lac contributed by 
Mr. Lowrie, depaty forest conservator, to the Nagpur Forest Conference of 190S. 



j|. 9, U. S. Dept. of Agriculture. 



Plate X. 




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Bui. 9, U. S. Dept. of Agriculture. 



Plate XI. 




Fig. 1 .—Cross Section of California-Grown Acacia melanoxylon, 18 Years 
Old; One of Several Trunks from the Same Root. 




Fig. 2.— Flats of Nursery-Grown Acacias Ready to be Set Out. 



AN ECONOMIC STUDY OF ACACIAS. 33 

A. microhotya, and in fact nearly every acacia which is grown in 
California yield useful gum. 

The best gum invariably comes from trees grown under arid con- 
ditions, and as a rule the quantity depends upon the climate and 
the yield increases with drought and summer heat. 

Perfumes. 

One species of acacia, Acacia farnesiana, the " cassie" of the French, 
takes high economic rank. It is said to have been known to Dios- 
corides, a Greek medical writer of the second century. Bentham 
thought this species was indigenous to western America from Chile 
to Texas and also to northern Australia; Von Mueller says: "Indig- 
enous to south Asia westward as far as Japan. Acacia acnifera, 
endemic on the Bahamas, is very closely related to A. farnesiana." It 
is now known, however, that A. farnesiana is native to the high pla- 
teaus of central Africa. Mr. J. M. Purvis, chief forest officer, Nyassa 
Land Protectorate, writing recently from Zomba, has reported to the 
author that A. farnesiana is very common there. 

Mr. H. Nehiiing describes specimens in Florida 16 feet high and 
only 8 years old. Mr. H. Plant reports a 30-foot tree in northern 
Mexico. In California the largest are now from 20 to 25 feet high. 
Dense thickets of this acacia grow near the ruins of San Diego Mission 
and about other Spanish settlements. As a shrub it is not as hand- 
some as many others, but it is perfectly adapted to large areas in 
America, because it is considerably hardier than the Australian 
species and thrives better in regions of summer rams. 

The acacia-perfume industry, as carried on prmcipally at Grasse, 
France, is very attractive and profitable. A full-grown tree yields 
about 300 pounds of flowers. The industry has been so often de- 
scribed that all the details of the extraction of the perfume are 
readily accessible. All that needs to be noted here is that a number of 
Australian acacias, such as A. pycnantha and A. suavolens, are used for 
the production of perfumes as well as A. farnesiana. The industry 
utilizes poor soils mcapable of bearmg grain or fruit crops, and gives 
light and pleasant outdoor employment to women and children. 

Dyes, Medicines, Foods, and Fibers. 

Several species of Australian and South American acacias furnish 
yellow, brown, and red dyes which are both cheap and easily obtained. 

Bentham, Von Mueller, Maiden, and others have investigated the 
medicinal properties of acacias, but the subject, like that of acacia 
dyes, requires more work from specialists. It is generally known 
that all of the wattle acacias and many of the Asiatic and South 
American species are serviceably astringent. The pods and the galls 



34 BULLETIN 9, U, S. DEPARTMENT OF AGRICULTURE. 

which grow on some species are locally esteemed as medicines. 
Salicin and saponin are yielded abundantly by several of the Aus- 
tralian species. The food and fiber uses of the acacias, while inter- 
esting, are commercially unimportant, and are mainly confined to 
the Australian species. Thozet says that the roots of Acacia hid- 
willii are edible after baking. Wattle seeds require much boiling or 
roasting to make them palatable, and the seeds of many species give 
ofi^ a most disagreeable odor when cooked. No acacia is cultivated 
primarily as a food plant. 

PROPAGATION AND MANAGEMENT OF ACACIAS. 

The conditions which govern successful acacia growing are not 
complex and should be readily understood by any intelligent planter. 
Nevertheless, there have been many failures in the propagation of 
acacias and large unnecessary expense. There can be no profit in 
growing trees of any sort for tanbark, timber, or fuel unless the 
expense is far below that of a nurseryman's ordinary outlay, which 
of course includes the cost of many transplantings and much han- 
dling of the stock. If healthy trees, well established, can not be 
obtained at less than half a cent a piece, the forest management of 
acacias will not be profitable. As a matter of fact, however, trees 
can be obtained at this low price. 

planting. 

Direct Seeding. 

The simple and natural way to secure an acacia plantation is to 
sow the seed where it is desired that the trees -shall stand. This is 
the method followed, with local modifications, m South Africa, 
Algeria, India, and Australia. The method has never been adopted 
in California, however, except experimentally on a small scale, yet 
there is little reason to doubt that it will be successful in connection 
with a careful study of local conditions. In no other way can large 
plantations be cheaply established. 

The seeds of acacias resemble those of common locust (Rohinia 
pseudacacia), though generally smaller, and like them have a thick, 
hard, protective shell. Their germinative power and ability to 
grow rapidly is very great, and few classes of tree seeds are so well 
adapted to make a start and to maintain life under difficult conditions. 
In nearly all cases the seed has to be prepared for rapid germination. 
The Australian authorities say that it will sometunes remain dormant 
in the ground for years. Dr. Hilgard has noted an instance at 
Berkeley, Cal., where young acacias came up 14 years after the parent 
tree had been removed. Since no other tree of the same species 
was anywhere in the neighborhood, it is probable that the seed had 
lain all that time without germinating. Especially in light soils and 



AN ECONOMIC STUD?' OF ACACIAS. 35 

in seasons of scanty rainfall it seems wise, therefore, to assist the 
germinating process. Usually this is done by placing seed in a vessel 
and pouring over it boilmg water, leaving the seed to soak and swell 
for from 24 to 48 hours. Seed may even be boiled for some minutes 
without injury. 

Seed may be prepared for germination by dry as well as by moist 
heat; in other words, it may be more or less roasted. After every 
fire in the Australian "bush" perfect forests of young wattles spring 
upo Some planters burn brushwood to embers and then mix the 
acacia seed with ashes and dying coals, leaving it for several days. 
Sometunes, too, seed may be shaken in a frying pan over the fire. 

In California it has been observed that acacia seedlings come up 
abundantly where piles of acacia brush have been burned, usually in 
rings several inches wide around each brush pile. Where the short, 
dry grass and weeds under acacia groves have been burned reproduc- 
tion has been assisted both in quantity and distribution. 

The following tests, reported by Mr. J. E. Brown (Australia) 
show the effects of various treatments of the seed: 

Acacia pycnantha. — Five parcels of seed saturated with water at temperatures of 
150° F., 170°, 190°, 200°, and 212°, respectively. All germinated well in three weeks. 
Four parcels of seed boiled for 1, 3, 5, and 7 minutes, respectively. All germinated 
in 18 days. 

Acacia saligna'.—Seed saturated in boiling water germinated in one week. 

Acacia decurrens .—Seed saturated with boiling water and then swelled in wet sand. 
Germinated in two weeks. 

Tests made for this report on California grown seed are as follows: 

Acacia pycna7Uha.Seed boiled for 5 minutes germinated 30 per cent in 4 days, 
with nearly all of the remaining seed still sgund at the end of 11 days. 

Acacia melanoxijlon.Seed boiled 2 minutes germinated 20 per cent at the end of 
11 days. Boiled 7 minutes germinated 6 per cent. Much of the seed, however, was 
sound and simply required more time to sprout. 

Acacia cyanophylla.—Seed boiled 2 minutes germinated 70 per cent; boiled 5 
minutes germinated 64 per cent; boiled 10 minutes germinated 4 per cent. 

After the seed has been heated it may be mixed with damp sand 
and left until sprouting before it is sown. The objections to this 
process are that it can not then be drilled and the seedling is more 
likely to succumb in case of protracted dry weather. Mr. Perrin, 
state conservator of forests, Victoria, mixes half a bushel of sand 
with each pound of seed and broadcasts. Some planters sow the seed 
on top of plowed ground ; others cover with a harrow. Where there is 
a loose soil sheep may be driven over the tract to tread in the seed. 
Often barley is sown with the acacia seed to serve as a shelter. It is 
said that some successful plantations have been started in the scrub 
in Australia. Possibly there are places in California where the 
chaparral could be broadcasted with profit, but as a rule clearing is 
necessary. It is claimed that the seed of tanbark acacias is hardly 



36 BULLETIN 9, U. S.' DlJ^AETMENT OF AGRICULTURE. 

ever subject to depreciations by rodents, and that gophers will not 
gnaw their r^ots. 

After a plantation is established the natural way to secure repro- 
duction is to depend upon self-sown seedlings. It is likely, however, 
that these may come up irregularly, and that the use of the drill or 
transplants may be necessary to secure a uniform stand. The 
mere fact that acacias become naturalized and spread over waste 
places m parts of India, Africa, Algeria, California, and the South- 
west does not necessarily imply that well-stocked groves can be 
produced invariably without aiding nature. 

The method of planting known in the Forest Service as seed 
spotting, equivalent to planting in hills, has several advantages over 
broadcastmg. It saves a great deal of seed; it enables the planter 
to pick out the best spots and to prepare them with some care; and 
it greatly reduces the cost of subsequent thmnings. In many cases 
land may be so well prepared that seed could be drilled hi or sown 
by hand in rows. Thorough cultivation of the ground is of course 
desu'able, yet excellent plantations have been established with less 
cost of time and labor. For example, at Mount Benson, South 
Australia, where the soil is very poor — the mere white sand of the 
"fern hills" — double furrows 8 feet apart were struck out. Seed 
which had been soaked hi boiling water was drilled hi and covered 
with a harrow, 1 pound to the acre. In some places it would be 
practicable to attach drill and harrow to the plow and complete the 
whole planting operation at one time. One man and a team can 
plant S acres a day. 

Use op Nursery Stock. 

Nursery methods are too expensive for the forester except to sup- 
plement field sowing. They mvolve skilled labor and the use of 
considerable material such as seed boxes and flats and pots, either of 
paper or clay. In Indi<a sections of bamboo" are used for the plants, 
which are set in the ground as soon as the seedling is ready for the 
field. In Australia stems of the reed Arundo donax have been used 
at a cost of $1.25 a thousand tubes, this price including the cutthig 
of the reeds, fiUmg the sections with earth, and setthig out the plants. 

California nurserymen sow their acacia seed beds hi June, July, 
and August, and the plants are ready to be transplanted to pots or 
to be set out the following spring. The seed-bed method entails a 
heavy loss, and boxes, flats, or trays are usually preferable and 
cheaper. These flats are generally 4 inches deep and contain 2 or 3 
square feet. Each one will hold from 100 to 200 plants of transplant 
size. Generally they are sheltered from sun and wind by lath houses, 
by brush, or by being placed under large trees. One laborer can 
care for many thousaiid of these smaU acacias in the flats, which 



A-N" ECONOMIC STUDY OF ACACIAS. 37 

need only to be watered every evening and to be thinned so that the 
plants will stand an inch or so apart. 



SPROUTING AND LAYERING. 



All the tanbark wattles sprout readily from the stump, and this 
method of crop reproduction is especially valuable when acacias are 
grown for firewood. The sand-reclaiming acacias will root even from 
the recumbent stems. This helps them to spread over the ground. 
This natural layering process can be aided by slashing the lower 
branches, bending them down, and covering the gash with earth. 
A. saligna and A. longifolia thus treated spread almost as well as 
willows. 

GENERAL CONCLUSIONS. 

The most important fact derived from an economic study of 
acacias m California is that after some fifty years many species of 
acacia have proven themselves to be entirely at home over large 
areas, and have in fact become naturalized. They are worth the 
• careful investigation of tree planters and foresters, for they fill a 
place which is not occupied by any other group of exotic trees. 
Since many of them make only slight requirements on moisture and 
soil, theu' cultivation need not interfere with that of other exotic 
trees for special products, such as the Japanese chestnut, cork oak, 
camphor tree, date palm, eucalypts, algaroba or carob, and maritime 
pine. 

The unique field occupied by acacia tanbark and by some other 
products, especially the gums, and the usefulness of the best acacia 
woods would seem to justify the general conclusion that plantations 
properly located and managed are as likely to prosper in America as 
m other countries. But before extensive commercial operations are 
decided upon there is need for more complete and painstakmg work 
upon the acacias — their growth and their products — the study to 
be based upon American-grown trees. As yet the rates of growth 
and the yields of various species on different soils, especially under 
plantation conditions, are not definitely determined. Unless such 
preliminary scientific investigation is undertaken and its evidence 
accepted, it is likely that mdustries based upon acacias may be 
exploited too hastUy, and, therefore, present failures will give seV 
backs such as have resulted where the culture of any particular tree 
has become a fad. These failures are likely to do much to deter 
properly qualified persons from entering upon an industry which 
should ultimately become established on solid foundations. 

So far, acacias have been planted iji the United States simply as 
ornamentals, and the information secured from a study of these 
specimens has been chiefly cultural. They have proved that the 



38 BULLETIN 9, U. S. DEPAETMENT OF AGRK q qqq nmimm 

best acacias thrive in California, and that they will grow on poor 
and arid soils, where there is little or no frost. Beyond this there is 
not much mformation, and some mismformation. For example, 
they are commonly bracketed with the eucalypts in the minds of 
many persons, simply because the eucalypts and most of the acacias 
come from Australia. The place occupied by the acacias, however, is 
as distmct from that of the eucalypts as both are from oaks or from 
conifers. 

To successfully develop commercial plantations of acacias in the 
United States, at least three problems will need to be solved. First, 
the behavior of the trees under close-planted commercial conditions 
must be known, and this can be learned only from experimental 
plantations. Second, the various labor-saving economies will have 
to be studied, and methods standardized, because American economic 
conditions are markedly different from those of Natal, Hawaii, the 
Transvaal, and Australia. Thii'd, and probably most unportant 
and difficult, wUl be the problem of marketing the products in com- 
petition with those produced cheaply abroad. 

It wUl probably be very easy for American planters to duplicate 
the working plans of acacia growers elsewhere, or even to improve 
upon them as far as American conditions wUl induce changes in 
details. Successful acacia culture depends primarily upon good 
farm practice. Hard-workmg, practical men, even without special 
trainmg in forestry, have created great plantations. It is likely that 
the same thing wUl occur in this country. At the same time the 
true spirit of scientific investigation, the power of observuig and 
drawing correct conclusions are essential to the development of this 
industry along new lines. 

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